But it's not nearly as bad as it sounds. "It looks gross and it feels gross, but it actually doesn't taste gross at all," Duncan Biddulph said. "It just kind of tastes like brandade. It tastes very much like cod, and it's a little salty, which I guess is normal for that sort of thing."

Cod milt is most common in Japanese cuisine, where it's steamed, fried, or occasionally served raw with ponzu or another sauce. It's in season during the winter, so anyone who wants to try it now is in luck. Biddulph got some fresh from his fish purveyor, but he also bought a large frozen block of it from an Asian market in Chicago. Asked how many cod were required to make the two-and-a-half-pound brick, he said, "I don't know. Cod are pretty big fish, and—I don't know their prowess as lovers. I don't know how virile they are."

He recommends buying the milt fresh rather than frozen, though. "When it comes in fresh, at least you can identify it as having had been part of an animal as opposed to maybe something that you would build a little shack out of."

A sous chef from Kuma's Corner who came in to Rootstock for dinner got to taste one of Biddulph's early creations with cod milt. "I sent him out some extra courses and asked if he liked weird food, so he said yes and promptly got a cod milt on toast with black butter and capers and parsley. Said it was incredible. Loved it. Freak."

Despite the popularity of that dish, Biddulph went in another direction for his final creation, incorporating the milt into a Japanese-style egg custard called chawanmushi. He briefly poached a few pieces, noting that he didn't want to overcook them because they'd get hard and granular in texture, like overcooked liver. "It's about halfway cooked in the middle," he said after taking it out.

Tasting a bit, he said, "It's pretty OK at this point. Just kind of tastes like seawater, really." He hadn't tasted it raw, though, and didn't want to. "It's got a really squidgy texture, where if you kind of pinch the membrane, it breaks and you wind up with seminal fluid on your hands. It's so much fun."

Biddulph forced the poached milt through a tamis, then combined it with eggs and dashi and steamed the mixture in a water bath until the custard set. To go on top, he made a kind of salad with shiitakes pickled in fish sauce and fermented tomato vinegar; toasted sesame seeds; a vinaigrette of ponzu, lime cells, mustard, and olive oil; and microgreens and celery leaves, finishing it off with salmon roe. "Maybe we'll end up with a mutant, cod sperm and salmon roe," he said. "Ugh, what have we created?"

Biddulph also fried a few small pieces of poached cod milt to top off the custard. Tasting it, he said, "Wow, that is really good"—but he also made a face. He explained why: "It was crunching through the cod milt, kind of feeling it press against my tongue, and then instantly popping one of the salmon eggs against the roof of my mouth to make those mix together—that was a little fish overload. But once you start crunching on the celery leaves and the shiitake and all of that—I don't know. It's got a really round flavor. Deep and bright."

While he doesn't anticipate putting the dish on his menu anytime soon, Biddulph said he's planning to serve it to Rodney Staton next time he comes in for dinner.

Who's Next:

Jason Hammel of Lula Cafe, working with gjetost (also known as brunost), a whey cheese in which the milk sugar is caramelized, making the resulting product sweet. "Not really the greatest food ever, but I think it's got a lot of potential," Biddulph said. "I don't think it's gross. It's just a little weird."

Cod milt chawanmushi (savory egg custard)

Bring water to a boil in a pot on the stove, and place several pieces of cod milt in it for 30 seconds, then remove to a cold water bath. Reserve a few small pieces, and force the rest through a tamis until you have several tablespoons.

Beat the eggs lightly, creating as few air bubbles as possible. Add the stock and salt to the eggs and strain through a tamis, then mix in the strained cod milt. Pour into small ceramic bowls and place them into a hot water bath on a stovetop, cover with cling film, and steam over high heat for two minutes. Turn flame to medium and steam for 12 more minutes, or until set.

Meanwhile, make a salad of the pickled mushrooms, salmon roe, celery leaf, and ponzu vinaigrette. Deep-fry the reserved pieces of poached cod milt. When the egg custard is done cooking, top it with the salad and fried milt and then serve.